WO 96/28427 describes benzamidine anticoagulants of the formula: ##STR2## wherein Z.sup.1 and Z.sup.2 are O, N(R), S or OCH.sub.2 and the central ring may be phenyl or a variety of heterocycles. The presently claimed compounds do not contain the Z.sup.1 linker or the substitution pattern of the above compounds.
WO 95/18111 addresses fibrinogen receptor antagonists, containing basic and acidic termini, of the formula: ##STR3## wherein R.sup.1 represents the basic termini, U is an alkylene or heteroatom linker, V may be a heterocycle, and the right hand portion of the molecule represents the acidic termini. The presently claimed compounds do not contain the acidic termini of WO 95/18111.
Activated factor Xa, whose major practical role is the generation of thrombin by the limited proteolysis of prothrombina holds a central position that links the intrinsic and extrinsic activation mechanisms in the final common pathway of blood coagulation. The generation of thrombin, the final serine protease in the pathway to generate a fibrin clot, from its precursor is amplified by formation of prothrombinase complex (factor Xa, factor V, Ca.sup.2+ and phospholipid). Since it is calculated that one molecule of factor Xa can generate 138 molecules of thrombin (Elodi, S., Varadis K.: Optimization of conditions for the catalytic effect of the factor IXa-factor VIII Complex: Probable role of the complex in the amplification of blood coagulation. Thromb. Res. 1979, 15, 617-629), inhibition of factor Xa may be more efficient than inactivation of throibin in interrupting th e blood coagulation system.
Therefore, efficacious and specific inhibitors of factor Xa are needed as potentially valuable therapeutic agents for the treatment of thromboembolic disorders. It is thus desirable to discover new factor Xa inhibitors.